According to reports from the World Health Organization, the number of blood donors worldwide is decreasing, while the global need for safe blood of all types continues to rise. Blood is running out.

But there's a solution. Doctors can help you make a backup blood supply by bioengineering some of your stem cells to produce blood cells in a petri dish. That's right - this transfusion method is already in use right now.

Using hematopoietic stem cells (called HSCs for short, hematopoeitic stem cells are the cells that give rise to all blood cell types) from a human donor, a team of researchers led by University of Paris's Luc Douay has managed to generate billions of red blood cells in culture (cRBCs) and inject them back into the donor's body.

Incredibly, the researchers showed that the lifespan and survival rate of the of injected cultured cells were comparable to those of the donor's native blood cells. What's more, their results indicate that the cultured cells were functional with regard to the following crucial points:

(i) their capacity to correctly bind oxygen in a reversible manner, to ensure their transport function, (ii) normal contents of G6PD and PK, to reduce glutathion and maintain a level of ATP sufficient to prevent the accumulation of 2,3 diphosphoglycerate (2,3 DPG), which lowers the affinity for hemoglobin and (iii) their deformability, which conditions the survival of the cells in vivo on account of their repeated passages through microvessels. As expected, the deformability is slightly diminished as compared to that of adult RBC, but similar to that of native reticulocytes from a healthy donor.

In other words, the cultured RBCs appear to have been introduced into the donor's body as seamlessly as blood from another human donor.

"Although previous research has shown that HSCs can be developed into fully matured red blood cells, this is the first study that has proven that they are capable of survival in the human body, a major breakthrough for the transplant community," said Douay. He continues:

There is a dire need for an alternative source of transfusable blood products, especially with the risk of infection from emergent new viruses that comes with traditional transfusion. Producing red blood cells in culture is promising since other efforts to create alternative sources have not yet been as successful as once hoped.

The results from our study establish the feasibility of the concept of transfusing cRBCs and show promise that an unlimited blood reserve is within reach.